WIND CLIMATOLOGY OF SINGAPORE : SPATIAL, TEMPORAL AND VERTICAL WIND PATTERNS

Abstract

This research aims to study the spatial, temporal and vertical wind patterns in Singapore. Wind plays a major role in determining the climate of an area. Substantially more work has been done on the urban heat island effect than on wind patterns in Singapore. Before any idea of the effects of local wind on Singapore's climate can be formulated, the patterns of variation should be understood in more detail than is currently the case. Differences in wind patterns exist both between seasons and stations.

Wind velocities and directions from the 5 wind stations run by the Singapore Meteorological Service (SMS) were obtained for the study. In addition to these data, vertically distributed windspeeds were measured at heights of 4.6 m, 13.0 m and 24.2 m through original fieldwork done at Bishan New Town. The data collected were then processed with various statistical packages and the output used to produce charts for comparison of the spatial and temporal variations.

Distinct diurnal trends in windspeeds were observed throughout the year, with lower windspeeds before sunrise and after sunset, with an early afternoon peak. Wind directions did not show such a clear-cut diurnal pattern, but did exhibit some land-sea breeze directional changes in the relative frequencies of winds from the north and south in the course of the day.

Spatial patterns of variation were more complicated, but the study showed that there were indeed differences between stations. Much of the differences depended on "upwind" features, especially the presence of high rise public housing estates, which dominate the Singapore landscape by their sheer extent and high degree of clustering. Such building clusters serve to reduce windspeeds in the built-up area as well as alter the wind flow to the surrounding areas, by dynamical interactions with the prevailing winds.

Turbulence was observed at the fieldwork site at all 3 heights under study. A significant vertical gradient of wind velocities was observed to exist between the lower and higher levels at Bishan New Town through the field work.

The findings of this study suggest that there is a spatial pattern on a finer scale than is currently covered by the network of wind stations. Hence, similar studies utilising more data collection points could help obtain a more detailed map of the wind patterns of Singapore. This information would be of immense value for city planning purposes.